Tamper evident closure

Abstract

In accordance with the present invention, an irreversible tamper evident system for a closure such as a button closure is provided. The irreversible tamper evidence system is provided by an appearance change system carried by the flexible button portion of the closure. The appearance change system comprises a liquid crystal material and a liquid crystal poison. When the button is depressed such as upon initial closure of the container, the liquid crystal material is separated from the liquid crystal poison and optical properties of the liquid crystal material are viewable. When the container is opened the flexing the button forces the liquid crystal poison into contact with the liquid crystal material and the optical properties of the liquid crystal material are irreversibly altered.

What is claimed is: 
     
       1. A tamper evident closure comprising a closure including a flexible end panel portion having formed therein a sealing state indicating area which can flex from a seal indicating position to a non-seal indicating position, a cover in overlying relationship to said sealing state indicating area, a liquid crystal indicator housed between the external surface of said sealing state indicating area and the interior surface of said cover, said liquid crystal indicator having distinct optical properties viewable through said cover when said flexible end panel is in a seal indicating position, means for irreversibly disrupting said liquid crystal indicator, said means positioned to irreversible disrupt said liquid crystal indicator when said flexible end panel flexes to its non-seal indicating position whereby when said flexible end panel flexes to its non-seal indicating position said distinct optical properties irreversibly change. 
     
     
       2. The closure of claim 1 wherein said liquid crystal indicator comprises an iridescent liquid crystal material. 
     
     
       3. The closure of claim 1 wherein said cover comprises a rigid transparent plastic material. 
     
     
       4. The closure of claim 3 wherein said liquid crystal indicator is carried by the internal surface of said cover. 
     
     
       5. The closure of claim 1 wherein said means comprises a liquid crystal poison material. 
     
     
       6. The closure of claim 5 wherein said poison comprises an absorbent material. 
     
     
       7. The closure of claim 6 wherein said absorbent material is dark colored and is secured to the external surface of said sealing state indicating area. 
     
     
       8. A tamper evident closure comprising a closure including a flexible end panel portion having formed therein a sealing state indicating area which can flex from a seal indicating position to a non-seal indicating position due to the release of energy stored within said end panel, said sealing state indicating area carrying a liquid crystal poison, a rigid transparent window secured to said closure in overlying relationship to said sealing state indicating area, said window carrying a liquid crystal indicator having distinct optical properties on its interior surface, said liquid crystal indicator being separate from said poison and viewable through said window when said end panel is in a seal indicating position, said poison and said liquid crystal indicator being positioned so that when said flexible end panel flexes to its non-seal indicating position said poison interacts with said liquid crystal indicator to cause an irreversible change in the optical properties of said liquid crystal indicator. 
     
     
       9. The closure of claim 8 wherein said poison is an absorbent material. 
     
     
       10. The closure of claim 8 wherein said poison is a chemical which is intersoluble with said liquid crystal indicator. 
     
     
       11. The closure of claim 8 wherein said window is plastic.